Efficacy of Electrical Baroreflex Activation Is Independent of Peripheral Chemoreceptor Modulation

Area of Science:

• Cardiovascular Physiology
• Hypertension Research
• Neuroautonomic Function

Background:

• Arterial baroreflex activation via electrical carotid sinus stimulation is a treatment for resistant hypertension.
• Peripheral chemoreflex activation may inhibit baroreflex responses in hypertensive patients.
• The interaction between baroreflex and chemoreflex in hypertension is not fully understood.

Purpose of the Study:

• To investigate whether peripheral chemoreflex activation attenuates baroreflex efficacy during electrical carotid sinus stimulation in patients with resistant hypertension.
• To explore baroreflex-chemoreflex interactions in humans with resistant hypertension.

Main Methods:

• 11 patients with resistant hypertension and implanted electrical carotid sinus stimulators were studied.
• Baroreflex responses to electrical stimulation were assessed under normoxia, isocapnic hypoxia, and hyperoxia.
• Measurements included blood pressure, heart rate, ventilation, and muscle sympathetic nerve activity.

Main Results:

• Electrical baroreflex activation reduced blood pressure, heart rate, and muscle sympathetic nerve activity during normoxia.
• Hypoxia activated the peripheral chemoreflex, increasing blood pressure, heart rate, muscle sympathetic nerve activity, and ventilation.
• Responses to electrical carotid sinus stimulation were similar during hypoxia and hyperoxia, indicating no attenuation by chemoreflex activation.

Conclusions:

• Moderate peripheral chemoreflex activation does not attenuate acute responses to electrical baroreflex activation therapy in patients with resistant hypertension.
• These findings provide novel insights into human baroreflex-chemoreflex interactions in the context of resistant hypertension.